Updated June 2026 · runs 100% in your browser
Watermark PDF
Stamp a diagonal text watermark across every page on your device. No upload, no sign-up.
Drop PDF files here
or click to choose
🔒 Processed on your device · 0 bytes uploaded
How it works
ConvertCabin draws your watermark text across each page with pdf-lib, in your browser. Your PDF is never uploaded.
It stays free, unlimited and private, and works offline once loaded.
About Watermark PDF
A watermark marks a document as a draft, confidential or yours. This stamps semi-transparent text diagonally across every page, leaving the original content readable underneath.
Tips & common uses
Adding a watermark stamps text or a mark across each page of a PDF — useful for marking status, ownership, or confidentiality before sharing.
- Marking drafts with 'DRAFT' or 'CONFIDENTIAL' so versions aren't confused.
- Asserting ownership by stamping your name or company on documents you distribute.
- Flagging copies as 'SAMPLE' or 'NOT FOR DISTRIBUTION' before sending externally.
- Dating or numbering a document set for tracking.
Frequently asked questions
How do I watermark a PDF?
Drop a PDF, type your watermark text, set opacity and angle, and download the result — all in your browser.
Can I make it more or less visible?
Yes — the opacity slider controls how faint or bold the watermark appears.
Is my PDF uploaded?
No. The watermark is applied on your device with pdf-lib; nothing is sent to a server.
What is a PDF file?
PDF (Portable Document Format) preserves a document's exact layout, fonts, and images on every device and operating system, which is why it's the standard for sharing files that must look identical everywhere.
Does the watermark go on every page?
Yes — the mark is applied across all pages of the PDF in one pass.
Is my PDF uploaded to add the watermark?
No. The watermark is applied in your browser, so the document never leaves your device.